The present invention relates to a bioelectrical impedance measuring apparatus for measuring an electrical impedance of a human body by use of four electrodes to determine a body fat ratio, body water, blood pressure or the like.
In a conventional body fat scale with a body weight scale for measuring a bioelectrical impedance by use of four electrodes to calculate a body fat ratio and others (hereinafter referred to as xe2x80x9cbody fat scalexe2x80x9d), the four electrodes A1, B1, C1 and D1 are arranged on a cover 100a of the main body 100 of the body fat scale, as shown in FIG. 9. Upon superimposing both foot soles of a subject on the electrodes A1, B1, C1 and D1, the bioelectrical impedance is measured and then the measured body weight, body fat ratio and others are displayed on a display 101.
In order to suppress undesirable influences of differences among subjects, such as differences between adults and children or differences in foot size, the electrodes A1, B1, C1 and D1 of the conventional body fat scale have been designed in large. This has led to increased cost of components and uncomfortable chilly feeling from foot soles superimposed on such electrodes.
It is an object of the present invention to provide a bioelectrical impedance measuring apparatus capable of solving the aforementioned problems.
In order to achieve this object, according to a first aspect of the present invention, there is provided a bioelectrical impedance measuring apparatus including a measurement board and two pairs of electrodes arranged on the measurement board, wherein a bioelectrical impedance of a subject is detected with bringing both foot soles of the subject into contact with the electrodes, characterized in that each of the two pairs of electrodes is arranged to extend approximately radially from the center of the measurement board.
In the first aspect of the present invention, the two pairs of electrodes may comprise a first pair of adjacent electrodes and a second pair of adjacent electrodes. In this case, each of the first pair of adjacent electrodes may serve as a current supply electrode, and the distance between respective lower portions of the first pair of adjacent electrodes may be less than the distance between respective upper portions of the first pair of adjacent electrodes. Further, each of the second pair of adjacent electrodes may serve as a voltage measuring electrode, and the distance between respective upper portions of the second pair of adjacent electrodes may be less than the distance between respective lower portions of the second pair of adjacent electrodes. Preferably, positioning means for positioning a heel of the subject may be provided near each of the second pair of adjacent electrodes serving as a voltage measuring electrode.
According to a second aspect of the present invention, there is provided a bioelectrical impedance measuring apparatus including a measurement board and two pairs of electrodes arranged on the measurement board, wherein a bioelectrical impedance of a subject is detected with bringing both foot soles of the subject into contact with the electrodes, characterized in that the two pairs of electrodes are arranged to surround the center of the measurement board.
In the second aspect of the present invention, the two pairs of electrodes may comprise a first pair of adjacent electrodes and a second pair of adjacent electrodes. In this case, each of the first pair of adjacent electrodes may serve as a current supply electrode, and the distance between respective lower portions of the first pair of adjacent electrodes may be greater than the distance between respective upper portions of the first pair of adjacent electrodes. Further, each of the second pair of adjacent electrodes may serve as a voltage measuring electrode, and the distance between respective upper portions of the second pair of adjacent electrodes may be greater than the distance between respective lower portions of the second pair of adjacent electrodes. Preferably, positioning means for positioning a heel of the subject may be provided near each of the second pair of adjacent electrodes serving as a voltage measuring electrode.
In one embodiment, convex positioning means may be provided near each of the first pair of adjacent electrodes serving as a current supply electrode.